Chess clock



FIG. 1 is a perspective view of a chess clock of the present invention;

FIG. 2 is a Front Elevation View of the chess clock of the present invention;

FIG. 3 is a Rear Elevation View of the chess clock of the present invention;

FIG. 4 is a left side elevation of the chess clock; and,

FIG. 5 is a top plan view of the chess clock. 

CLAIM The ornamental design for a chess clock, as shown. 